auto burst trigger

Discussion in 'Gunsmithing Forum' started by 223, Jun 3, 2011.

  1. 223

    223 New Member

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    I recently purchased an auto burst trigger. Its a mechanical peace that basically works like bump firing. It bolts to the trigger guard and uses the recoil of the gun to fire like an automatic. It comes with a card stating that it is ATF approved. My question is, while it works, my ar15 wont fire all the bullets. The firing pin strikes the primer and the ammo doesn't fire. I have tried different brands of ammo with the same results. I can kick the bullet out reload it and it will fire. Is this because my carrier isn't designed for full auto firing?
     
  2. Sniper03

    Sniper03 Supporting Member Supporter

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    223,

    It is legal with the ATF due to the fact that it technically is not auto fire. Auto fire is when the trigger is pulled to the rear and held and the rifle fires in auto mode until the operator lets go of the trigger or the magazine runs empty.
    The device you have still requires the trigger to be activated or pulled per each round. Even though it is by the device, as it is pulled by the action you described.
    Being as the AR-15 Rifle is a Gas Impingement System and requires a certain amount of resistance which is usually accomplished by the shooter having the stock against his or her shoulder. Like a pistol required resistance for the slide to go to the rear and eject the spent case. The AR requires a certain amount of the same requirement. This allows the bolts rearward motion to function properly. In this pump fire operation you are talking about it may not have the resistance required causing the bolt to short cycle, which could also cause the round not to eject, or load correctly, or for that matter even the hammer to not cock correctly all the time. Also a though try a "New" Magazine! A brand new magazine! Not just another one.
    The other issue is the small indentation you are talking about regarding the perceived firing pin problem. That is not it. Since the Firing Pin in a AR-15 or 16 series rifle is an inertia firing pin. Any round that has been loaded in the rifle and the bolt and carrier dropped from the open bolt position by either pulling the charging handle and letting it go. Or by depressing the Bolt Catch Release Button. Or loaded from a magazine after the proceeding round has been fired under normal operation will have this slight dent in the primer. That is a normal condition. So if you have been holding the weapon of to the side to use this trigger devise and not solidly supporting the rifle that could cause your present problem. It also not to get too in depth, could be the amount of gas and the gas port size the weapon has. Obviously if it is a weapon that has minimal gas to function that could cause the problem by inadequate support. While a gun that was what we call running a little hot would function if not totally supported. You mentioned ammunition. You might try some full blown tactical ammunition in the 69 grain area like Federal Tactical. If this does not work. Sell the trigger unit. There is a compatibility problem.
    Good Luck!
    03
     

  3. Jpyle

    Jpyle New Member

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    ^^^what he said. I would also add that you are operating a semi-auto beyond its design tolerances. Excess heat, hammer, trigger reset and bolt cycle time may not synch properly resulting in an improper contact of the firing pin to the primer. Technically similar to a short stroke. A select fire rifle is designed as such, the device you use is forcing the issue by rapidly pulling the trigger not by a bolt driven, properly timed, dropping of the hammer. Just my .02.
     
  4. 223

    223 New Member

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    Thanks. Think im going to lose the auto burst trigger and take the proper steps to get a license for a full auto and purchase a gun set up properly.
     
  5. Sniper03

    Sniper03 Supporting Member Supporter

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    223,

    You must find an auto weapon that was produced and transferable prior to March of 1986. *Federal Firearms Act. Not being a law enforcement or government agency you can not buy a new one. Manufacturers can not manufacture or sell to anyone including an individual police officer after that date. The class III Auto Weapon must be owned by the agency or government entity. And for example, an M-16 A-1 that would be legal for purchase by an individual and transferable will run anywhere from $12,000-$16,000. You would also have to transact the sale and transfer of the weapon through a Class III Dealer. And purchase your Federal Tax Stamp for the weapon at an additional $200.00.+
    Bottom line to own an auto weapon it is not an easy task as mentioned in the hoops above.
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